Improved Concentration Capabilities of Flat-Plate Fresnel Lenses

2010 ◽  
Vol 74 ◽  
pp. 188-195 ◽  
Author(s):  
Maxim Z. Shvarts ◽  
Andrey A. Soluyanov
Keyword(s):  
Light Flux ◽  
Optical Power ◽  
Fresnel Lens ◽  
Calculation Model ◽  
Minimum Size ◽  
Size Analysis ◽  
Focal Distance ◽  
Optical Efficiency ◽  
Fresnel Lenses ◽  
Lens Formation

This paper presents an experience in designing, manufacturing and testing the Fresnel lenses (FLs) for sunlight concentration in photovoltaic modules with multi-junction solar cells (SCs). A power ray tracing model is used for calculating and optimizing refractive profile parameters and obtaining optical-power characteristics (OPCs) of Fresnel lenses. In searching the optimum combination of the lens aperture, its focal distance and profile configuration, the optimization criterion was the maximum of the average sunlight concentration at high optical efficiency in the focal spot of minimum size. Analysis of characteristics of circular Fresnel lenses with conical (the facet generating lines are straight ones) and curvilinear (the facet generating lines are curved ones) refracting surfaces has been carried out. The effect material parameters on the lens optical efficiency were studied. Molds for Fresnel lens formation and experimental specimens were fabricated and a control of their profile parameters has been done. A degree of the effect of the light flux characteristics and Fresnel lens geometrical imperfections on validity of the experimental data interpretation has been examined. The correction procedure have been applied in the calculation model to establish the lens optical efficiency values at standard irradiance conditions.

Two Types of Calorimeters for Assessing Fresnel Lens Performance in Concentrating Solar Systems

2011 ◽  
Author(s):  
Aaron Sahm ◽  
Robert Boehm ◽  
Kwame Agyenim-Boateng ◽  
Ken Hynes ◽  
Kim Hammer ◽  
...  
Keyword(s):  
Steady State ◽  
Temperature Rise ◽  
Focal Point ◽  
Focal Length ◽  
Fresnel Lens ◽  
Lumped Mass ◽  
Optical Efficiency ◽  
Concentration Process ◽  
Mass Approximation ◽  
Fresnel Lenses

Concentrating solar energy systems can use either refractive or reflective approaches to achieve the desired concentration ratio. However this is done, there is always a question about what the flux might actually be incident on the target of interest after the concentration process. Assessing the losses due to the concentration process is quite important in understanding the overall performance of the solar concentrating system. An issue that impacts this measurement is the type of system being evaluated, as the total flux at the focal point could be quite large. We have been working with concentrating PV units that utilize acrylic Fresnel lenses to achieve the necessary concentration on a single multi-junction cell. The magnitude of the losses associated with these types of lenses was desired. We developed two calorimeters for the purpose of evaluating the optical efficiency of Fresnel lenses utilized in various point focus concentrating systems. The first calorimeter developed utilizes a transient technique whereby a time-measured pulse of the beam is directed to a mass of material in a cavity form. The material has a high conductivity, so the lumped mass approximation can be used for the analysis of the energy absorbed if the temperature rise of the material is measured. The other calorimeter developed was a steady-state type that employs a technique commonly known as flow calorimetry. In this approach, the concentrated flux is beamed into the core of the calorimeter which is cooled to some steady-state value of temperature with a liquid (water near the ambient temperature was used in our tests). Knowing the liquid flow rate and temperature rise of the fluid allows the total heat input to be assessed. This paper discusses the development, testing, and comparison of the two calorimeters. Results are given for the evaluation of several types of commercial acrylic Fresnel lenses having different characteristics such as groove density and focal length.

scholarly journals Researches on the development of an optical system for improving the efficiency of photovoltaic panels

2020 ◽  
Vol 180 ◽  
pp. 02008
Author(s):  
Dana Rizescu ◽  
Ciprian Ion Rizescu ◽  
Cristian Gabriel Alionte
Keyword(s):  
Fresnel Lens ◽  
Lens Model ◽  
Focal Points ◽  
Matlab Simulation ◽  
Focal Distance ◽  
Manufacturing Costs ◽  
Photovoltaic Panel ◽  
Planar Convex ◽  
Fresnel Lenses

The paper aims to create a unit using Fresnel lenses. This module consist of an arrangement of planar-convex Fresnel lenses, made of methyl polymethacrylate, mounted in a hexagonal raster and bent to form a dome for collecting and amplifying solar radiation at several focal points and with the possibility of adjusting the focal distance. The module has three aluminum alloy legs that are vertically adjustable. This construction using Fresnel lenses mounted in a hexagonal raster will increase the energy collected by a photovoltaic panel, thus significantly reducing energy losses and long-term costs. Compared to normal lenses, these lenses are considerably lighter because the material in the center of the lens is reduced, and for manufacturing can be used methyl polymethacrylate or polycarbonate, thus greatly reducing manufacturing costs. To show the functioning of the unit the authors presents in the paper a MATLAB simulation of the Fresnel lens model and a ray propagation.

scholarly journals Influence of a Thermal Pad on Selected Parameters of Power LEDs

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3732
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Tomasz Torzewicz ◽  
Marcin Janicki
Keyword(s):  
Optical Properties ◽  
Thermal Resistance ◽  
Optical Power ◽  
Junction Temperature ◽  
Operating Parameters ◽  
Cold Plate ◽  
Optical Efficiency ◽  
Forward Current ◽  
Measurement Results ◽  
Set Up

This paper is devoted to the analysis of the influence of thermal pads on electric, optical, and thermal parameters of power LEDs. Measurements of parameters, such as thermal resistance, optical efficiency, and optical power, were performed for selected types of power LEDs operating with a thermal pad and without it at different values of the diode forward current and temperature of the cold plate. First, the measurement set-up used in the paper is described in detail. Then, the measurement results obtained for both considered manners of power LED assembly are compared. Some characteristics that illustrate the influence of forward current and temperature of the cold plate on electric, thermal, and optical properties of the tested devices are presented and discussed. It is shown that the use of the thermal pad makes it possible to achieve more advantageous values of operating parameters of the considered semiconductor devices at lower values of their junction temperature, which guarantees an increase in their lifetime.

scholarly journals Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4301
Author(s):  
Yassir A. Alamri ◽  
Saad Mahmoud ◽  
Raya Al-Dadah ◽  
Shivangi Sharma ◽  
J. N. Roy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Numerical Study ◽  
Single Point ◽  
Optical Element ◽  
Fresnel Lens ◽  
Electrical Performance ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Optical Efficiency ◽  
Concave Lens

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

A Novel High Concentration Fresnel Lens as a Solar Concentrator

2021 ◽  
pp. 1-29
Author(s):  
Kuldeep Awasthi ◽  
Desireddy Shashidhar Reddy ◽  
Mohd. Kaleem Khan
Keyword(s):  
Optical Axis ◽  
Spherical Aberration ◽  
Spherical Surface ◽  
Fresnel Lens ◽  
High Concentration ◽  
Aperture Diameter ◽  
Convex Lens ◽  
Flat Base ◽  
Fresnel Lenses ◽  
Outer Vertex

Abstract This paper describes the design methodology for a novel Fresnel lens. The original Fresnel lens is obtained from a plano-convex lens, whose spherical surface is split into a number of divisions (called facets), collapsed onto the flat base. Thus, all the facets of the original Fresnel lens have the same radius as that of the plano-convex lens. The proposed design aims to achieve better ray concentration and reduced spherical aberration than the original Fresnel lens by constructing spherical facets with unequal radii. The centers and radii of facets are constrained so that the ray refracted from the bottom vertex of each facet on one side of the optical axis and the ray refracted from the outer vertex of the corresponding facet on the other side of the optical axis must intersect at the focal plane. The proposed lens design has resulted in a 275% gain in the concentration ratio and a 72.5% reduction in the spherical aberration compared to the original lens of the same aperture diameter and number of facets. The performance of both novel and original Fresnel lenses when used as solar concentrators with a conical coil receiver is evaluated. The novel Fresnel lens led to increased heat gain and resulted in a compact solar collector design.

scholarly journals The effectiveness of a mini photovoltaic cell by using light LED bulbs as a source of photon energy

2021 ◽  
Vol 926 (1) ◽  
pp. 012090
Author(s):  
Mustofa ◽  
Iskandar ◽  
Muchsin ◽  
S Suluh ◽  
T M Kamaludin
Keyword(s):  
Energy Source ◽  
Output Power ◽  
Electrical Energy ◽  
Photovoltaic Cell ◽  
Fresnel Lens ◽  
Test Results ◽  
Light Spectrum ◽  
Pv Cell ◽  
Fresnel Lenses ◽  
Cell Module

Abstract Muxindo’s LED bulb is one of the brands that are widely used by Indonesian people as lighting in the home. This study aims to look at the effectiveness of the light spectrum of the 10, 15 and 20 Watt LED power bulbs as an energy source to generate electrical energy in monocrystalline mini photovoltaic (PV) cell module. The light spectrum is compared with and without the Fresnel lens before being transmitted to the PV surface. The test results show that the PV output power is much better with a Fresnel lens (4.06> 1.67) mW. The efficiency of PV with lens displays slightly different figures, 3.77% at 15 Watt bulb power, while without Fresnel lenses, PV efficiency is 4.86% with a 20 Watt bulb. Need further research, for example, with Philips brand LED bulbs

Using SiO2 Hard Mask for Fabrication of Micro Fresnel Focusing Lens for Ultrasonic Ejectors

2020 ◽  
Vol 863 ◽  
pp. 73-78
Author(s):  
Tuan Anh Bui ◽  
Min Chun Pan ◽  
Tzon Han Wu ◽  
Thanh Long Le
Keyword(s):  
Process Parameters ◽  
Side Wall ◽  
Fresnel Lens ◽  
Sio2 Film ◽  
Hard Mask ◽  
Fabrication Procedure ◽  
Fresnel Lenses ◽  
Wall Profile ◽  
Focusing Lens

The fabrication of Fresnel focusing lenses operating at frequencies of 100 and 200 MHz was investigated in order to enhance the focusing efficiency of ultrasonic energy. The effects of process parameters on the four-level Fresnel lens profiles were discussed to find a most feasible fabrication procedure through these experiments. The quality of Fresnel lenses was improved when two-and three-mask processes using SiO2 film as the hard mask were employed. Besides, a better side-wall profile of Fresnel lens was obtained by using the three-mask process as compared to the two-mask one.

Estimation by radiation inactivation of the minimum functional size of acrosome-reaction-including substance (ARIS) in the starfish, Asterias amurensis

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 351-355 ◽  
Author(s):  
Akira Ushiyama ◽  
Kazuyoshi Chiba ◽  
Akihiro Shima ◽  
Motonori Hoshi
Keyword(s):  
Acrosome Reaction ◽  
Functional Unit ◽  
Sugar Content ◽  
High Energy ◽  
Target Size ◽  
Minimum Size ◽  
Size Analysis ◽  
Asterias Amurensis ◽  
Total Sugar Content ◽  
Jelly Coat

SummaryIn the starfish Asterias amurensis, the jelly coat of the eggs contains a glycoprotein essential for the induction of the acrosome reaction in homologous spermatozoa that is termed the acrosome-reaction-inducing substance (ARIS).ARIS is a highly sulphated and fucose-rich glycoprotein of extremely high molecular mass(>104 kDa). ARIS was irradiated with high-energy eletrons in order to estimate the minimum size required for its biological activity. The minimum functional unit or target size of ARIS was estimated to be c. 14 kDa by target size analysis. ARIS was significantly disintegrated by the irradiation, yet the total sugar content was not apparently reduced. The binding of 125I-labelled ARIS to spermatozoa competed with that of irradiated ARIS, although the affinity of ARIS was much reduced after irradiation.

Optical Parameters in High-Efficiency Optical Receivers With a Parabolic Reflector Before and After Coating With Ag Film

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Chung Jui Lee ◽  
Jen Fin Lin
Keyword(s):  
High Efficiency ◽  
Film Coating ◽  
Fresnel Lens ◽  
Optical Parameters ◽  
Optical Receivers ◽  
Profile Error ◽  
Optical Efficiency ◽  
Aspheric Lens ◽  
Before And After ◽  
Ag Film

High-efficiency optical receivers before and after the coating of Ag film are composed of a parabolic reflector, a solid parabolic second optical element (SOE), and a Fresnel/aspheric concentrating lens. The optical receivers before the Ag-film coating are fabricated on a high-precision machine tool based on an optimum design attained from ray tracing software simulations. The real profiles of the reflector before and after coating the Ag film are found to be the average of the two orthogonal parabolic profiles. They are then compared to the perfect profile (without profile error and surface roughness) in order to investigate the influence of the profile error and the Ag film on optical performances. The optical parameters, including the total flux, the optical efficiency, and the maximum, minimum, and mean irradiances are evaluated for ray projection simulations in the ASTM G173-03 spectrum. Experiments for the same ray source are also carried out to compare with the simulation results. It is determined that Ag-film coating can improve the profile error and surface roughness of the reflector, thus resulting in all optical parameters being either equal to or higher than those of the reflector without Ag coating. The total flux and optical efficiency obtained from the module with the Fresnel lens has values relatively higher than those of the aspheric lens. The irradiance uniformity for the Fresnel lens is also determined to be better than that of the aspheric lens. The irradiance intensity of the reflector after coating the Ag film has a magnitude at various wavelengths higher than that of the reflector without the Ag-film coating. Due to the coating of the Ag film, the optical receiver shows an almost constant rise in optical efficiency for the two types of concentrating lenses. This characteristic is shown to be valid for both the simulation and experimental results.

Maintenance of genetic polymorphism under conditions of genotype-dependent growth and size-selective mortality

1985 ◽  
Vol 27 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Robert A. Desharnais ◽  
David W. Foltz ◽  
E. Zouros
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
General Pattern ◽  
Fishing Effort ◽  
Minimum Size ◽  
Size Analysis ◽  
Fishing Mortality ◽  
Biochemical Basis ◽  
Important Species ◽  
Dependent Growth

Associations between heterozygosity at one or more electrophoretically detected enzyme loci and growth rate have been reported for several species of plants and animals, including several commercially important species of finfish and shellfish. The general pattern is for heterozygotes to grow faster than homozygotes, although there is some variation in growth response even within a species. Regardless of the physiological or biochemical basis of genotype-dependent growth, polymorphism at a locus affecting growth rate in an overdominant manner may be lost if larger individuals have a greater mortality rate than smaller ones. In an exploited population, mortality of this sort is likely to result from size-selective fishing pressure. Using a continuous-time single-locus model of natural selection, we have related the maintenance of polymorphism at a locus to two measures of fishing effort: β, the legal minimum size below which there is no mortality, and f, an instantaneous mortality rate owing to fishing (above the legal minimum size). We considered two different models of fishing mortality. In model 1, fishing mortality above the legal minimum size is constant; in model 2, fishing mortality is a linear function of size (above β). Numerical analysis of model 1 indicates that maintenance of polymorphism requires either a low rate of fishing mortality or a value of β that is close to zero or close to the maximum attainable size. Analysis of model 2 gives similar results, suggesting that the conclusions are not dependent on the exact form of the mortality function.Key words: heterozygosity, growth, size, mortality.

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